1. Field of the Invention
The present invention relates to an apparatus for and method of manufacturing an article of footwear having a minimal number of upper pieces. More particularly, the present invention relates to an apparatus for and method of manufacturing an athletic shoe, walking shoe, brown shoe, dress shoe or boot wherein the number of pieces required to construct the footwear upper is minimized in relation to known manufacturing processes.
2. Related Art
Shoe manufacture is a labor intensive process. The typical shoe manufacturing process encompasses the steps of cutting the upper material, reducing the thickness of the joining edges (xe2x80x9cskivingxe2x80x9d), reducing the thickness of the upper pieces (xe2x80x9csplittingxe2x80x9d), cementing the interlining to the upper pieces (xe2x80x9cinterliningxe2x80x9d), forming the eyelets, stitching the upper pieces together, shaping the upper over a last (xe2x80x9clastingxe2x80x9d) and cementing, molding or sewing the bottom of the shoes to the upper (xe2x80x9cbottomingxe2x80x9d). Modern footwear designs, particularly athletic shoe designs, require numerous upper pieces and complicated manufacturing steps, leading to high labor costs. Additionally, a new pattern is required and the manufacturing process must be retooled for every new design and style and for each desired shoe size.
In an effort to reduce labor costs, published PCT application WO 90/03744, incorporated herein by reference, describes the use of heat embossing to minimize the number of manufacturing steps. The published application describes a process of manufacturing shoe components, including an entire one-piece upper, in which a multi-layered upper material is heat embossed in a compression mold to reduce the thickness of the material, to close or seal the edges, to incorporate a functional design or pattern lines, and for strain management. After the embossing step, the backsides of the embossed upper material are stitched together by means of a back strip and the upper material is lasted and bottomed to form the completed shoe. This process greatly reduces the cutting and stitching steps and can eliminate the skiving, splitting and interlining steps of the typical shoe manufacturing process.
However, the shoe manufacturing process disclosed in the published PCT application does not greatly reduce the assembly time and costs associated with creating new patterns and retooling the manufacturing process for new designs, new styles and different shoe sizes. Rather, a new pattern and a new embossing mold must be created for each change in design and a separate embossing mold must be used for each desired shoe size. Similarly, numerous upper materials, in varying colors and textures must be kept in inventory to accommodate desired changes in style.
What is needed therefore is an improved labor-saving and time-saving method of shoe manufacture requiring less retooling time and reduced retooling costs. Further, what is needed is an improved shoe-manufacturing method in which the required upper material inventory is reduced. Still further, what is needed is a flexible, low cost shoe-manufacturing method that can be used to form a wide variety of shoe styles and designs.
The present invention is directed to a process for manufacturing an article of footwear having a single or multi-layer upper, wherein the number of pieces required to construct the footwear upper is minimized in relation to known manufacturing processes.
In one embodiment, the article of footwear manufactured has a three layer upper, having a minimal number of upper pieces. The process comprises the steps of molding a one-piece outer layer and a one-piece middle layer of the upper, with an embossing tool, described below, such that the desired appearance of the upper is embossed on the outer layer and such that the outer layer and middle layer are adhered to one another. Alternatively, the molding step can be omitted, if it is not desired to emboss the outer and middle layers, and the outer layer and middle layer can be adhered to each other by a conventional adhesive.
The ends of this one-piece outer layer/middle layer combination are then joined and stitched, using methods known to those skilled in the art, to form a conventional upper shape. A back strip of material having a pull tab may be sewn to the inside and/or outside of the outer layer/middle layer combination at the seam created by joining the ends.
A third, one-piece, inner layer is also formed into the shape of the footwear upper by joining and stitching the ends of the inner layer, such that the inner layer has a single seam. The inner layer is then inserted within the outer layer/middle layer construction and the inner layer is stitched to the middle layer to form the three layer upper of the present invention.
A combined tongue overlay and tongue pull tab, which may be molded in the embossing tool, described below, such that the desired appearance of the upper is embossed on this piece, may be stitched onto the tongue area of the three layer upper construction to further define the tongue shape and appearance. Eyelet stay reinforcers and lace loops may be disposed around the tongue area of the upper, as is conventional in the art. Similarly, a heel counter and heel collar may be disposed in the heel area of the upper, as is conventional in the art, to provide further comfort and support.
Finally, the three layer upper is lasted and the lasted upper is cemented, molded or sewn to the desired sole to complete the shoe construction. The upper can be decorated to create the final desired color and appearance, using a process such as screen printing, sublimation, large format ink jet printing, cold and hot peel transfers, fabric dyeing or multi-layered digital printing, either before or after the molding step, as discussed below.
Similar multi-layer one-piece upper constructions can be manufactured according to the present invention having two, four or more layers, as would be apparent to one of ordinary skill in the art, by either removing or adding one or more of the above mentioned layers.
Similarly, a single layer upper construction can be manufactured according to the present invention, having a one-piece upper material formed into the shape of the desired footwear upper. This material can be molded, as discussed below, in an embossing tool such that the desired appearance of the upper is embossed on the upper material. The ends of the upper material are stitched together using methods known in the art, and a back strip of material having a pull tab may be sewn to the inside and/or outside of the upper material at the seam where the ends are stitched together. A combined tongue overlay and tongue pull tab, which may be molded in the embossing tool, described below, such that the desired appearance of the upper is embossed on this piece as well, may be stitched onto the tongue area of the upper material to further define the tongue shape and appearance. Eyelet stay reinforcers and lace loops may be disposed around the tongue area of the upper material, as is conventional in the art. Similarly, a heel counter and heel collar may be disposed at the heel area of the upper material, as is conventional in the art, to provide further heel comfort and support. Finally, the upper material is lasted and the lasted upper is cemented, molded or sewn to the desired sole to complete the shoe construction. The upper material can be decorated to create the final desired color and appearance, using a process such as screen printing, sublimation, large format ink jet printing, cold and hot peel transfers, fabric dyeing or multi-layered digital printing, either before or after the molding step, as discussed below.
The present invention is also directed to an embossing tool for manufacturing a one-piece upper. The embossing tool can be utilized for more than one shoe size, model, design or style, and comprises an embossing mold and removable texture plates disposed in the embossing mold. Additionally the embossing mold may also comprise a combination of whole or partial plates, used for forming an upper, that can be interchanged within the embossing mold and/or within themselves. For example, an entire upper plate can be removed from the embossing mold and can be replaced with another upper plate design option. These upper plate design options can also have interchangeable inserts or texture plates for additional flexibility in the process. By interchanging the removable, texture plates disposed in the upper plate of the embossing mold, different textures and appearances for the upper can be created using the same basic embossing mold.
The present invention is also directed to a process for molding a one-piece upper material, utilizing the embossing tool according to the present invention. This improved manufacturing process includes the step of molding the upper material with an embossing tool having removable texture plates, such that the desired appearance of the upper is embossed on an upper material. The improved shoe manufacturing process according to the present invention greatly reduces the retooling time and costs associated with changes in the design and style of the upper. By interchanging the removable texture plates disposed in the embossing mold, different textures and appearances can be created using the same basic upper pattern, thereby, reducing retooling time and costs.
Additionally, the improved shoe manufacturing process of the present invention includes the step of decorating the upper material with the desired colorway onto a base color upper material before or after the molding step. The art of decorating the upper material includes, but is not limited to, screen printing, sublimation, large format ink jet printing, cold and hot peel transfers, fabric dyeing and multi-layered treatment, for example digital printing different layers of images on top of one another. Thus, the improved shoe manufacturing process according to the present invention allows for multiple or different colorways to be created with a single base color upper material, minimizing the need to order and have in inventory materials of different colors and reducing retooling time and costs, such that changes in decorative appearance can be quickly generated.
Therefore, the tool and process according to the present invention exhibit great flexibility with respect to aesthetics, construction and cost values, allowing for the creation of an unlimited variety of upper appearances in a number of sizes with minimal retooling time and costs. Additionally, the present invention reduces the costs and time associated with the shoe manufacturing process by reducing the number of upper pieces required and the amount of manual labor involved in the retooling process. By increasing the design flexibility of the manufacturing process, the present invention reduces the number of manufacturing steps and, thereby, reduces the amount of labor involved.